// Copyright 2006-2009 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// CPU specific code for arm independent of OS goes here.
#ifdef __arm__
#ifdef __QNXNTO__
#include <sys/mman.h> // for cache flushing.
#undef MAP_TYPE
#else
#include <sys/syscall.h> // for cache flushing.
#endif
#endif

#if V8_TARGET_ARCH_ARM

#include "src/cpu-features.h"

namespace v8 {
namespace internal {

    // The inlining of this seems to trigger an LTO bug that clobbers a register on
    // arm, see https://crbug.com/952759#c6.
    __attribute__((noinline)) void CpuFeatures::FlushICache(void* start,
        size_t size)
    {
#if !defined(USE_SIMULATOR)
#if V8_OS_QNX
        msync(start, size, MS_SYNC | MS_INVALIDATE_ICACHE);
#else
        register uint32_t beg asm("r0") = reinterpret_cast<uint32_t>(start);
        register uint32_t end asm("r1") = beg + size;
        register uint32_t flg asm("r2") = 0;

#ifdef __clang__
        // This variant of the asm avoids a constant pool entry, which can be
        // problematic when LTO'ing. It is also slightly shorter.
        register uint32_t scno asm("r7") = __ARM_NR_cacheflush;

        asm volatile("svc 0\n"
                     :
                     : "r"(beg), "r"(end), "r"(flg), "r"(scno)
                     : "memory");
#else
        // Use a different variant of the asm with GCC because some versions doesn't
        // support r7 as an asm input.
        asm volatile(
            // This assembly works for both ARM and Thumb targets.

            // Preserve r7; it is callee-saved, and GCC uses it as a frame pointer for
            // Thumb targets.
            "  push {r7}\n"
            // r0 = beg
            // r1 = end
            // r2 = flags (0)
            "  ldr r7, =%c[scno]\n" // r7 = syscall number
            "  svc 0\n"

            "  pop {r7}\n"
            :
            : "r"(beg), "r"(end), "r"(flg), [scno] "i"(__ARM_NR_cacheflush)
            : "memory");
#endif
#endif
#endif // !USE_SIMULATOR
    }

} // namespace internal
} // namespace v8

#endif // V8_TARGET_ARCH_ARM
